<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>CSS火环效果</title>
    <link rel="stylesheet" href="index.css">
</head>
<body>
    <div class="circle"></div>
    <div class="circle"></div>
    <svg>
        <filter id="wavy">
            <feTurbulence x="0" y="0" baseFrequency="0.009" numOctaves="5" seed="2">
                <animate attributeName="baseFrequency"  dur="60s" values="0.02;0.005;0.02" repeatCount="indefinite"/>
            </feTurbulence>
            <feDisplacementMap in="SourceGraphic" scale="30"/>
        </filter>
    </svg>
</body>
</html>